Wireless communications circuitry with simultaneous receive capabilities for handheld electronic devices

ABSTRACT

Handheld electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry has simultaneous reception functions that allow the handheld devices to simultaneously receive multiple communications signals in a single communications band. The handheld electronic devices may include cellular telephones with music player functionality or other portable devices. The handheld electronic devices may have local wireless communications capabilities for supporting local wireless links such as WiFi and Bluetooth links. Using the simultaneous reception functions of the wireless communications circuitry, users of the handheld electronic devices can simultaneously receive signals such as WiFi and Bluetooth signals.

This application is a continuation of patent application Ser. No.11/636,879, filed Dec. 11, 2006, which is hereby incorporated byreferenced herein in its entirety.

BACKGROUND

This invention relates generally to wireless communications circuitry,and more particularly, to wireless communications circuitry withsimultaneous receive capabilities for handheld electronic devices.

Handheld electronic devices are becoming increasingly popular. Examplesof handheld devices include handheld computers, cellular telephones,media players, and hybrid devices that include the functionality ofmultiple devices of this type.

Due in part to their mobile nature, handheld electronic devices areoften provided with wireless communications capabilities. Handheldelectronic devices may use long-range wireless communications tocommunicate with wireless base stations. For example, cellulartelephones may communicate using cellular telephone bands at 850 MHz,900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for MobileCommunications or GSM cellular telephone bands). Handheld electronicdevices may also use short-range wireless communications links. Forexample, handheld electronic devices may communicate using the WiFi®(IEEE 802.11) band at 2.4 GHz and the Bluetooth® band at 2.4 GHz.

To satisfy consumer demand for small form factor wireless devices,manufacturers are continually striving to reduce the number ofcomponents that are used. For example, in some wireless designs a singleantenna is shared by two transceivers. Because there is only a singleantenna with this type of approach, device size is minimized.

It is not always desirable to share an antenna in a wireless device. Inconventional shared antenna arrangements with two transceivers operatingon a shared communications frequency, the two transceivers compete witheach other for use of the antenna. If, for example, data is beingreceived by one of the transceivers, data cannot be received by theother transceiver. This may lead to dropped data packets and serviceinterruptions.

It would therefore be desirable to be able to provide improved wirelesscommunications circuitry for wireless handheld electronic devices.

SUMMARY

In accordance with an embodiment of the present invention, a handheldelectronic device with wireless communications circuitry is provided.The handheld electronic device may have cellular telephone, musicplayer, or handheld computer functionality. The wireless communicationscircuitry may have multiple transceivers that share an antenna.

With one suitable arrangement, the wireless communications circuitry hasfirst and second transceivers.

The first transceiver may be, for example, a wireless local area network(WLAN) transceiver integrated circuit that handles IEEE 802.11 traffic.The second transceiver may be a Bluetooth transceiver. The firsttransceiver and second transceiver may operate in a common frequencyband (e.g., a 2.4 GHz communications frequency band).

The wireless communications circuitry may have a radio-frequency couplerand switching circuitry. When it is desired to simultaneously receiveincoming radio-frequency signals from the antenna with both the firsttransceiver and the second transceiver, the coupler is used to dividethe incoming radio-frequency signals into first and second identicalpower-reduced versions of the incoming radio-frequency signals. Thesesignals are simultaneously provided to the first and second transceiversin parallel.

The first and second versions of the incoming signals that are producedby the coupler may have the same signal power or may have differentsignal powers. With one suitable arrangement, the coupler is asymmetric,so that the signal that is diverted to the wireless local area networktransceiver circuit has a relatively larger power than the signal thatis diverted to the Bluetooth transceiver.

When it is desired to transmit WLAN data, the switching circuitry isadjusted appropriately and the WLAN transceiver is made active while theBluetooth transceiver is made inactive. A power amplifier may be used toamplify outgoing transmitted WLAN data.

When it is desired to use the Bluetooth transceiver without using theWLAN transceiver, the WLAN transceiver is placed in an inactive state.When the WLAN transceiver is inactive, it is not necessary to receivedata simultaneously with both the WLAN and Bluetooth circuits. As aresult, the switching circuitry can be adjusted to bypass the coupler.With the coupler bypassed, Bluetooth data can be transmitted orBluetooth data can be received. When receiving Bluetooth data in thisway, there is a relatively larger signal strength, because the insertionloss of the coupler is avoided. If desired, an input amplifier may beplaced upstream from the coupler to compensate for the coupler'sinsertion loss.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative handheld electronicdevice with wireless communications circuitry in accordance with anembodiment of the present invention.

FIG. 2 is a schematic diagram of an illustrative handheld electronicdevice with wireless communications circuitry in accordance with anembodiment of the present invention.

FIG. 3 is a schematic diagram of conventional wireless communicationscircuitry for a wireless electronic device.

FIG. 4 is a schematic diagram of illustrative wireless communicationscircuitry for a handheld electronic device in accordance with anembodiment of the present invention.

FIG. 5 is a schematic diagram of an illustrative coupler that may beused in wireless communications circuitry for a handheld electronicdevice in accordance with an embodiment of the present invention.

FIG. 6 is a table showing illustrative switch settings that may be usedwith wireless communications circuitry of the type shown in FIG. 4 inaccordance with an embodiment of the present invention.

FIG. 7 is a timing diagram that illustrates wireless activity associatedwith using communications circuitry such as the illustrative wirelesscommunications circuitry of FIG. 4 in accordance with an embodiment ofthe present invention.

FIG. 8 is an illustrative state diagram showing how wirelesscommunications circuitry in a handheld electronic device such as thewireless communications circuitry of FIG. 4 may be used to handlewireless data traffic associated with two different transceivers inaccordance with an embodiment of the present invention.

FIG. 9 is a schematic diagram of illustrative wireless communicationscircuitry using a 2:1 splitter and low noise amplifier in an input datapath in accordance with an embodiment of the present invention.

FIG. 10 is a schematic diagram of an illustrative three-way switch thatmay be used in wireless communications circuitry of the type shown inFIG. 4 in accordance with an embodiment of the present invention.

FIG. 11 is a schematic diagram of an illustrative three-way switch thathas been implemented using two two-way switches and that may be used inwireless communications circuitry of the type shown in FIG. 4 inaccordance with an embodiment of the present invention.

FIG. 12 is a schematic diagram of an illustrative Bluetooth transceiverand control circuit having an integrated two-way switch that may be usedin wireless communications circuitry for a handheld electronic device inaccordance with an embodiment of the present invention.

FIG. 13 is a schematic diagram of an illustrative wireless local areanetwork (WLAN) and Bluetooth transceiver and control circuit that may beused in wireless communications circuitry for a handheld electronicdevice in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention relates generally to wireless communications andmore particularly, to wireless communications circuitry that supportsantenna sharing in electronic devices such as portable electronicdevices.

An illustrative portable electronic device in accordance with anembodiment of the present invention is shown in FIG. 1. Portableelectronic devices such as illustrative portable electronic device 10may be laptop computers or small portable computers such as thosesometimes referred to as ultraportables. Portable electronic devices mayalso be somewhat smaller devices. Examples of smaller portableelectronic devices include wrist-watch devices, pendant devices,headphone and earpiece devices, and other wearable and miniaturedevices.

With one suitable arrangement, the portable electronic devices arehandheld electronic devices. Space is at a premium in handheldelectronics devices, so antenna-sharing arrangements for handheldelectronic devices can be particularly advantageous. The use of handhelddevices is therefore generally described herein as an example, althoughany suitable electronic device may be used with the wirelesscommunications functions of the present invention, if desired.

Handheld devices may be, for example, cellular telephones, media playerswith wireless communications capabilities, handheld computers (alsosometimes called personal digital assistants), remote controllers,global positioning system (GPS) devices, and handheld gaming devices.The handheld devices of the invention may also be hybrid devices thatcombine the functionality of multiple conventional devices. Examples ofhybrid handheld devices include a cellular telephone that includes mediaplayer functionality, a gaming device that includes a wirelesscommunications capability, a cellular telephone that includes game andemail functions, and a handheld device that receives email, supportsmobile telephone calls, and supports web browsing. These are merelyillustrative examples. Device 10 may be any suitable portable orhandheld electronic device.

Device 10 includes housing 12 and includes at least one antenna forhandling wireless communications. Housing 12, which is sometimesreferred to as a case, may be formed of any suitable materialsincluding, plastic, wood, glass, ceramics, metal, or other suitablematerials, or a combination of these materials. In some situations, case12 may be a dielectric or other low-conductivity material, so that theoperation of conductive antenna elements that are located in proximityto case 12 is not disrupted. In other situations, case 12 may be formedfrom metal elements. In scenarios in which case 12 is formed from metalelements, one or more of the metal elements may be used as part of theantenna(s) in device 10.

Any suitable type of antenna may be used to support wirelesscommunications in device 10. Examples of suitable antenna types includeantennas with resonating elements that are formed from a patch antennastructure, a planar inverted-F antenna structure, a helical antennastructure, etc. To minimize device volume, at least one of the antennasin device 10 may be shared between two transceiver circuits.

Handheld electronic device 10 may have input-output devices such as adisplay screen 16, buttons such as button 23, user input control devices18 such as button 19, and input-output components such as port 20 andinput-output jack 21. Display screen 16 may be, for example, a liquidcrystal display (LCD), an organic light-emitting diode (OLED) display, aplasma display, or multiple displays that use one or more differentdisplay technologies. As shown in the example of FIG. 1, display screenssuch as display screen 16 can be mounted on front face 22 of handheldelectronic device 10. If desired, displays such as display 16 can bemounted on the rear face of handheld electronic device 10, on a side ofdevice 10, on a flip-up portion of device 10 that is attached to a mainbody portion of device 10 by a hinge (for example), or using any othersuitable mounting arrangement.

A user of handheld device 10 may supply input commands using user inputinterface 18. User input interface 18 may include buttons (e.g.,alphanumeric keys, power on-off, power-on, power-off, and otherspecialized buttons, etc.), a touch pad, pointing stick, or other cursorcontrol device, a touch screen (e.g., a touch screen implemented as partof screen 16), or any other suitable interface for controlling device10. Although shown schematically as being formed on the top face 22 ofhandheld electronic device 10 in the example of FIG. 1, user inputinterface 18 may generally be formed on any suitable portion of handheldelectronic device 10. For example, a button such as button 23 (which maybe considered to be part of input interface 18) or other user interfacecontrol may be formed on the side of handheld electronic device 10.Buttons and other user interface controls can also be located on the topface, rear face, or other portion of device 10. If desired, device 10can be controlled remotely (e.g., using an infrared remote control, aradio-frequency remote control such as a Bluetooth remote control,etc.).

Handheld device 10 may have ports such as bus connector 20 and jack 21that allow device 10 to interface with external components. Typicalports include power jacks to recharge a battery within device 10 or tooperate device 10 from a direct current (DC) power supply, data ports toexchange data with external components such as a personal computer orperipheral, audio-visual jacks to drive headphones, a monitor, or otherexternal audio-video equipment, etc. The functions of some or all ofthese devices and the internal circuitry of handheld electronic devicecan be controlled using input interface 18.

Components such as display 16 and user input interface 18 may cover mostof the available surface area on the front face 22 of device 10 (asshown in the example of FIG. 1) or may occupy only a small portion ofthe front face 22. Because electronic components such as display 16often contain large amounts of metal (e.g., as radio-frequencyshielding), the location of these components relative to the antennaelements in device 10 should generally be taken into consideration.Suitably chosen locations for the antenna elements and electroniccomponents of the device will allow the antenna of handheld electronicdevice 10 to function properly without being disrupted by the electroniccomponents.

A schematic diagram of an embodiment of an illustrative handheldelectronic device is shown in FIG. 2. Handheld device 10 may be a mobiletelephone, a mobile telephone with media player capabilities, a handheldcomputer, a remote control, a game player, a global positioning system(GPS) device, a combination of such devices, or any other suitableportable electronic device.

As shown in FIG. 2, handheld device 10 may include storage 34. Storage34 may include one or more different types of storage such as hard diskdrive storage, nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory), volatile memory (e.g.,battery-based static or dynamic random-access-memory), etc.

Processing circuitry 36 may be used to control the operation of device10. Processing circuitry 36 may be based on a processor such as amicroprocessor and other suitable integrated circuits. With one suitablearrangement, processing circuitry 36 and storage 34 are used to runsoftware on device 10, such as internet browsing applications,voice-over-internet-protocol (VoIP) telephone call applications, emailapplications, media playback applications, operating system functions,etc. Processing circuitry 36 and storage 34 may be used in implementingsuitable communications protocols. Communications protocols that may beimplemented using processing circuitry 36 and storage 34 includeinternet protocols, wireless local area network protocols (e.g., IEEE802.11 protocols—sometimes referred to as WiFi®), protocols for othershort-range wireless communications links such as the Bluetooth®protocol, etc.)

Input-output devices 38 may be used to allow data to be supplied todevice 10 and to allow data to be provided from device 10 to externaldevices. Display screen 16 and user input interface 18 of FIG. 1 areexamples of input-output devices 38.

Input-output devices 38 can include user input-output devices 40 such asbuttons, touch screens, joysticks, click wheels, scrolling wheels, touchpads, key pads, keyboards, microphones, cameras, etc. A user can controlthe operation of device 10 by supplying commands through user inputdevices 40. Display and audio devices 42 may include liquid-crystaldisplay (LCD) screens, light-emitting diodes (LEDs), and othercomponents that present visual information and status data. Display andaudio devices 42 may also include audio equipment such as speakers andother devices for creating sound. Display and audio devices 42 maycontain audio-video interface equipment such as jacks and otherconnectors for external headphones and monitors.

Wireless communications devices 44 may include communications circuitrysuch as radio-frequency (RF) transceiver circuitry formed from one ormore integrated circuits, power amplifier circuitry, passive RFcomponents, one or more antennas, and other circuitry for handling RFwireless signals. Wireless signals can also be sent using light (e.g.,using infrared communications).

Device 10 can communicate with external devices such as accessories 46and computing equipment 48, as shown by paths 50. Paths 50 may includewired and wireless paths. Accessories 46 may include headphones (e.g., awireless cellular headset or audio headphones) and audio-video equipment(e.g., wireless speakers, a game controller, or other equipment thatreceives and plays audio and video content). In one illustrativescenario, paths 50 may include a wireless Bluetooth path that is used tosupport communications between a Bluetooth headset (one of accessories46) and device 10 and a wireless local area network (WLAN) path (e.g., aWiFi path) that is used to support communications between device 10 andcomputing equipment 48.

Computing equipment 48 may be any suitable computer. With one suitablearrangement, computing equipment 48 is a computer that has an associatedwireless access point (router) or an internal or external wireless cardthat establishes a wireless connection with device 10. The computer maybe a server (e.g., an internet server), a local area network computerwith or without internet access, a user's own personal computer, a peerdevice (e.g., another handheld electronic device 10), or any othersuitable computing equipment.

Wireless communications devices 44 may be used to support local andremote wireless links.

Examples of local wireless links include WiFi and Bluetooth links andwireless universal serial bus (USB) links. Because wireless WiFi linksare typically used to establish data links with local area networks,links such as WiFi links are sometimes referred to as WLAN links. Thelocal wireless links may operate in any suitable frequency band. Forexample, WLAN links may operate at 2.4 GHz or 5.6 GHz (as examples),whereas Bluetooth links may operate at 2.4 GHz. The frequencies that areused to support these local links in device 10 may depend on the countryin which device 10 is being deployed (e.g., to comply with localregulations), the available hardware of the WLAN or other equipment withwhich device 10 is connecting, and other factors.

With one suitable arrangement, which is sometimes described herein as anexample, device 10 communicates using both the popular 2.4 GHz WiFibands (802.11(b) and/or 802.11(g)) and the 2.4 GHz Bluetooth band usingthe same antenna. In this type of configuration, the antenna is designedto operate at a frequency of 2.4 GHz, so the antenna is suitable for usewith the 2.4 GHz radio-frequency signals that are used in connectionwith both the WiFi and Bluetooth communications protocols. Circuitry 44may include a coupler and other suitable circuitry that allows WiFi andBluetooth signals to be simultaneously received.

If desired, wireless communications devices 44 may include circuitry forcommunicating over remote communications links. Typical remote linkcommunications frequency bands include the cellular telephone bands at850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, the global positioning system(GPS) band at 1575 MHz, and data service bands such as the 3G datacommunications band at 2170 MHz band (commonly referred to as UMTS orUniversal Mobile Telecommunications System). In these illustrativeremote communications links, data is transmitted over links 50 that areone or more miles long, whereas in short-range links 50, a wirelesssignal is typically used to convey data over tens or hundreds of feet.

These are merely illustrative communications bands over which wirelessdevices 44 may operate. Additional local and remote communications bandsare expected to be deployed in the future as new wireless services aremade available. Wireless devices 44 may be configured to operate overany suitable band or bands to cover any existing or new services ofinterest. If desired, multiple antennas and/or a broadband antenna maybe provided in wireless devices 44 to allow coverage of more bands. Atleast one of the antennas (e.g., an antenna used for WiFi and Bluetoothcommunications at a common communications band frequency of 2.4 GHz) maybe shared, as this helps reduce the size of wireless communicationscircuitry 44 and therefore reduces the size of device 10.

In conventional wireless electronic devices in which an antenna isshared between multiple communications bands, switching circuitry isused to switch between different transceiver modules. While this type ofarrangement may be satisfactory in undemanding applications, a sharedantenna arrangement that is based solely on switching circuitry can beinadequate in many contemporary situations.

Conventional wireless communications circuitry that is based on atraditional shared-antenna architecture is shown in FIG. 3. Wirelesscommunications circuitry 52 includes antenna 54, which handlesradio-frequency signals at a frequency of 2.4 GHz. Switch 56 selectivelyconnects antenna 54 to switch port S1, S2, or S3. Ports S1 and S2 areconnected to wireless local area network (WLAN) integrated circuit 58 byrespective paths 66 and 68. Port S3 is connected to Bluetooth integratedcircuit 60 by path 70. Wireless local-area-network integrated circuit 58includes a WiFi transceiver and control circuitry. Bluetooth integratedcircuit 60 includes a Bluetooth transceiver and control circuitry. WLANcircuit 58 and Bluetooth circuit 60 communicate with each other usinghandshaking path 62. Paths 72 and 74 are used to provide data andcontrol signals to circuits 58 and 60.

WLAN circuit 58 controls the state of switch 56 using control path 64.When it is desired to transmit WLAN data, switch 56 is connected toposition S1, so that data can be transmitted from WLAN integratedcircuit 58 to antenna 54 over path 66. Switch 56 is connected toposition S2 when it is desired to receive data with WLAN circuit 58. Inposition S2, signals from antenna 54 are conveyed through switch 56 andover path 68 to WLAN circuit 58. Switch 56 has a third position—S3—thatis used when it is desired to transmit or receive Bluetooth signals. Intransmit mode, Bluetooth signals are transmitted to antenna 54 viatransmit/receive path 70 and switch 56. In receive mode, Bluetoothsignals that have been received by antenna 54 are conveyed to Bluetoothintegrated circuit 60 by switch 56 and path 70.

The conventional arrangement of FIG. 3 allows antenna 54 to be shared.WiFi traffic is handled by WLAN circuit 58 and Bluetooth traffic ishandled by Bluetooth circuit 60. Switch 56 can be switched between WLANcircuit 58 and Bluetooth circuit 60, so that circuits 58 and 60 are ableto take turns using antenna 54. Although WLAN circuit 58 and Bluetoothcircuit 60 cannot be used at the same time, switch 56 can be switchedquickly, so that circuits 58 and 60 are able to use antenna 54 in rapidsuccession.

Because switch 56 cannot be connected to both WLAN circuit 58 andBluetooth circuit 60 at the same time, it is necessary to prioritize.Consider, as an example, the situation in which a user of communicationscircuitry 52 is browsing the internet using WLAN circuit 58, while usingBluetooth connection 60 to control a wireless mouse. In this type ofsituation, circuits 58 and 60 can decide to favor the Bluetoothconnection over the WiFi connection. Whenever it is desired to connectto both the WLAN circuit 58 and the Bluetooth circuit 60 at the sametime, the Bluetooth circuit is favored.

With this type of prioritization scheme, the user of circuit 52 will beable to use the wireless mouse without noticeable interruption. However,because the Bluetooth connection is favored over the WLAN connection,WLAN data packets will occasionally be dropped.

For example, consider the situation in which Bluetooth activity ariseswhile requested internet data is being transmitted to WLAN circuit 58.To handle the Bluetooth activity, switch 56 will be connected to switchposition S3. Bluetooth data has priority over WLAN data, so the factthat WLAN circuit 58 is in the midst of receiving internet data isimmaterial and switch 56 is switched to position S3 to ensure that theBluetooth activity is handled properly.

Placing switch 56 in position S3 allows Bluetooth circuit 60 to transmitand receive Bluetooth data as needed. However, setting switch 56 toposition S3 prevents WLAN circuit 58 from receiving the internet datathat is being transmitted. As a result, some internet data packets willbe at least temporarily lost.

Data interruptions such as these are unavoidable using the conventionalwireless communications circuitry arrangement of FIG. 3, because it isnot possible to set switch 56 to a position that allows simultaneousreception of WLAN and Bluetooth data. Although data interruptions suchas these may be acceptable in noncritical applications, in somesituations the impact of lost data may be severe. For example, a usermight desire to use WLAN circuit 58 to support avoice-over-internet-protocol (VoIP) telephone call over the internet,while using a Bluetooth headset. In real-time audio applications such asthese, a high quality connection is critical. Using conventionalwireless communications circuit 52 of FIG. 3 may cause the VoIP voicesignal to break up due to lost data packets.

Wireless communications circuitry 76 in accordance with an illustrativeembodiment of the present invention is shown in FIG. 4. As shown in FIG.4, wireless communications circuitry 76 has an antenna 78. A filter 80and a direct current (DC) blocking capacitor (not shown) may be used tofilter out spurious noise from received signals. Circuitry 76 includesswitches 82 and 84 (labeled S1 and S2, respectively). Path 81 connectsfilter 80 and switch SW1.

Switch SW1 may be set to one of three positions, which are labeled A, B,and C in FIG. 4. Switch SW2 may be set to one of two positions, whichare labeled D and E in FIG. 4.

The states of switches SW1 and SW2 are controlled by control signalsprovided on control lines 106 and 104, respectively. With one suitablearrangement, the control signals are generated by transceiver andcontrol circuitry 108.

Transceiver and control circuitry 108 may contain two or moretransceiver circuit such as wireless local-area-network (WLAN) circuit110 and Bluetooth circuit 120. For clarity, a two-transceiver-circuitembodiment is described herein.

WLAN transceiver circuit 110 may be, for example, an integrated circuitthat handles IEEE 802.11(b) or 802.11(g) signals using WiFi transceiver112 and control circuitry 114. Bluetooth transceiver circuit 120 may be,for example, an integrated circuit that handles Bluetooth signals usingBluetooth transceiver 116 and control circuitry 118. Circuits 110 and120 may be provided as two separate integrated circuits that are mountedon a common circuit board, using a single integrated circuit, or usingmore than two integrated circuits. With one suitable arrangement, WLANcircuit 110 is an integrated circuit such as Part No. 88W8686 of MarvellSemiconductor, Inc. of Santa Clara, Calif. and Bluetooth circuit 120 isan integrated circuit such as a BlueCore4 device of CSR, Cambridge,England. Circuits 110 and 120 may communicate with each other overhandshaking path 126.

Each transceiver circuit handles a different type of wireless datatraffic. In the example of FIG. 4, WiFi traffic is handled usingwireless local-area-network (WLAN) circuit 110 and Bluetooth traffic ishandled using Bluetooth circuit 120. Each of these circuits interfaceswith antenna 78 and with circuitry on the handheld electronic device inwhich wireless communications circuitry 76 is being used.

Data and control paths 122 and 124 may be used to form communicationspaths between transceiver and control circuitry 108 and other circuitryon device 10 such as processing circuitry 36 of FIG. 2. Paths 122 and124 may be used to support any suitable type of data communications. Asan example, path 122 may be used to convey control and user data usingthe so-called secure digital input/output (SDIO) protocol. Paths 124 and122 may be formed of any suitable number of conductive lines. In theexample of FIG. 4, path 122 has been formed from a six-line bus and path124 has been formed from a four-line bus. This is merely illustrative.Paths such as paths 122 and 124 may be formed from single lines or usinglarger or smaller busses of multiple lines, if desired.

WLAN circuit 110 may transmit WLAN data wirelessly using datatransmission path 98. With the illustrative configuration of FIG. 4,path 98 can be dedicated to conveying transmitted data for circuit 110.Transmitted data on path 98 may be amplified by power amplifier 88.Corresponding amplified versions of the transmitted data signals on path98 may be provided to switch SW1 over path 100. To transmit data overantenna 78, control signals may be issued on path 106 that direct switchSW1 to connect path 100 to path 81 (switch position A). When switch SW1has been placed in position A and WLAN data is being transmitted overpath 98, wireless communications circuitry 76 of FIG. 4 may be referredto as operating in WLAN TX mode. In this mode of operation, Bluetoothoperations are temporarily blocked, so the position of switch SW2 isimmaterial.

Circuitry 76 may have a radio-frequency coupler 86. An illustrativecoupler 86 is shown in FIG. 5. As shown in FIG. 5, coupler 86 may beimplemented as a four-terminal device. Terminal 128 may be used toreceive radio-frequency input signals. Termination resistor 136 may becoupled between ground 138 and termination resistor terminal 132. Duringoperation, input signals that are provided to input terminal 128 aredivided into two corresponding output signals on outputs 130 and 134. Asshown by box 144, coupler 86 typically contains a network of componentssuch as inductors, capacitors, and resistors that cause input signals onpath 140 to become coupled onto path 142. As a result, part of the inputsignal power to coupler 86 is diverted to output terminal 134, whilepart of the input signal power to coupler 86 passes through to output130. The splitting ratio of the coupler 86 is typically fixed by thevalues of the components in network 144. With one suitable arrangement,the output signal on output terminal 130 is −1.8 dB lower in power thanthe power of the input signal on input terminal 128 and the power of thecoupled output signal on output terminal 134 is −6.5 dB lower than thepower of the input signal on terminal 128. As this example demonstrates,coupler 86 typically exhibits some internal loss.

In this example, the coupler produces output signals that differ byabout 4.7 dB. One output signal, which represents a first power-reducedversion of the received radio-frequency input signals to the coupler,has an output power that is 4.7 dB larger than the other output signal,which represents a second power-reduced version of the receivedradio-frequency input signals to the coupler. The use of a coupler thatproduces output signals with −1.8 dB and −6.5 dB outputs is, however,merely illustrative. For example, coupler 86 may produce output signalsin which the power for output 130 is equal to the power of output 134 oroutput signals in which the power for output 130 is greater than thepower of output 134. An advantage of using arrangements in which theoutput signal power for output 130 is greater than the output signalpower for output 134 is that this may divert a relatively small amountof power away from WLAN circuit 110, thereby helping to preserve properoperation of WLAN circuit 110 under adverse conditions. In general, thepower of the signal on output 130 may be any suitable amount greaterthan the power of the signal on output 134. For example, the power ofthe signal on output 130 may be 1 dB greater than the power of thesignal on output 134 or more. As another example, the power of thesignal on output 130 may be at least 2 dB greater than the power of thesignal on output 134. As a further example, the power of the signal onoutput 130 may be at least 3 dB greater than the power of the signal onoutput 134.

As shown in FIG. 4, coupler 86 may be used to provide wirelesscommunications circuitry 76 with support for a shared receive mode(shared RX mode). In shared RX mode, control signals may be issued oncontrol path 106 that place switch SW1 in position B and control signalsmay be issued on control path 104 that place switch SW2 in position D.With switches SW1 and SW2 configured in this way, data that is receivedon antenna 78 and that is provided to coupler 86 via shared input path92 is split into two identical parts, each having a potentiallydifferent signal power. A first part of the received data signal ispassed to WLAN circuit 110 on shared received data path 96. A secondpart of the received data signal is passed to Bluetooth circuit 120 viashared receive data path 94, switch SW2, and path 102. The data of thesignals provided to circuits 110 and 120 in the shared receive mode isthe same, but the powers of the signals is dictated by the coupler 86and may be different. For example, the power of the data signal on path96 may be −1.8 dB with respect to the incoming data signal on path 92,whereas the power of the data signal on path 102 may be −6.5 dB withrespect to the incoming data signal on path 92 (as an example).

During use of wireless communications circuitry 76 of FIG. 4 insimultaneous receive mode, WLAN circuit 110 and Bluetooth circuit 120may be in simultaneous operation, each handling respective portions ofthe incoming data. For example, when incoming data is an internetprotocol (IP) packet destined for WLAN circuit 110, that packet may bereceived and processed by WLAN circuit 110. When incoming data isBluetooth data destined for Bluetooth circuit 120, Bluetooth circuit 120may receive and process the incoming data. Circuits 110 and 120 may bepresented with both types of data (WLAN and Bluetooth), but candigitally recognize which type of data is being received and cantherefore respond only as appropriate. Although signal strengths arereduced somewhat by the presence of coupler 86, simultaneous datareception is supported, so that demanding applications such as VoIPcalls and Bluetooth audio can be simultaneously supported, withoutconcern for lost data packets.

When it is desired to transmit Bluetooth data or when it is desired toreceive Bluetooth data on a dedicated path without using coupler 86(i.e., to benefit from a higher Bluetooth input signal power whensimultaneous reception of WLAN data is not required), control signalsmay be issued on control path 106 that place switch SW1 in position Cand control signals may be issued on control path 104 that place switchSW2 into position E. In this configuration, which is sometimes referredto as Bluetooth TX or dedicated RX mode, path 90 may be used forBluetooth data transmission or for dedicated Bluetooth data reception.

During Bluetooth transmission, transmitted Bluetooth data from Bluetoothcircuit 120 is provided to switch SW2 over path 102. Switch SW2, whichis set to position E, conveys the outgoing Bluetooth data to switch SW1over path 90. Switch SW1, which is set to position C, conveys theoutgoing Bluetooth data to antenna 78 over path 81 and filter 80.

During dedicated RX mode, received Bluetooth data from antenna 78 andfilter 80 is received by switch SW1 over path 81. Switch SW1 is set toposition C, so switch SW1 directs the incoming Bluetooth data to switchSW2 over dedicated RX path 90. Because coupler 86 is bypassed in thismode, the signal power on path 90 is larger than it would have been hadthe signal been split by coupler 86. Because the signal power of theincoming Bluetooth signal is relatively high, it may exhibit a goodsignal-to-noise ratio. Switch SW2 is set to position E during dedicatedRX mode, so the incoming Bluetooth data is routed to Bluetooth circuit120 via path 102.

FIG. 6 contains a table that illustrates switch settings involved duringthe operation of wireless communications circuitry 76 of FIG. 4. Intable 146, an entry of “0” indicates that a corresponding switchposition is not being used, an entry of “1” indicates that acorresponding switch position is being used, and an entry of “X”indicates a don't care bit (the position of the switch is immaterial).

As shown in table 146, during WLAN TX mode, switch SW1 is set toposition A, whereas the setting of switch SW2 is immaterial. In WLAN TXmode, WLAN circuit 110 is active and transmits WLAN data using antenna78.

During shared RX mode, WLAN circuit 110 and Bluetooth circuit 120 areactive simultaneously. Switch SW1 is set to position B, whereas switchSW2 is set to position D. In shared RX mode, circuit 110 and circuit 120receive signals with somewhat reduced powers, but because both circuitsare simultaneously active, incoming data is not lost. The type ofcoupler 86 that is used in the shared RX path influences the signalpowers received by WLAN circuit 110 and Bluetooth circuit 120. Ingeneral, any suitable ratio of output powers may be produced by coupler86.

An advantage to using a coupler arrangement in which relatively more ofthe outgoing signal power is directed to WLAN circuit 110 than toBluetooth circuit 120 is that this type of arrangement favors the WLANcircuit over the Bluetooth circuit. WLAN links are often formed overlarger distances than Bluetooth links and may therefore require moreassistance in maintaining good signal quality. Bluetooth links are oftenformed with equipment that is in the immediate vicinity of device 10 andmay therefore require relatively less assistance in maintaining goodsignal quality. On balance, it is therefore often preferred to use acoupler 86 that produces an output signal on path 96 that has more powerthan the corresponding output signal on path 94.

Transceiver circuits such as circuits 110 and 120 in transceiver andcontrol circuitry 108 of FIG. 4 may be used to support any suitableprotocols. The use of circuits that support WiFi and Bluetooth links arebeing described as an example. FIG. 7 illustrates how circuits such ascircuits 110 and 120 may handle WLAN traffic and Bluetooth audiotraffic. In the example of FIG. 7, time is plotted on the horizontalaxis. According to Bluetooth audio protocol specifications, Bluetoothcircuit 120 will be active in Bluetooth time slots 148-1 and 148-2.During Bluetooth operations, Bluetooth circuit 120 alternates betweentransmitting data and receiving data. The Bluetooth time slots arelabeled “BT TX” (148-1) and “BT RX” (148-2) to indicate whetherBluetooth circuit 120 is transmitting or receiving Bluetooth data.During time slots 150, Bluetooth circuit 120 is inactive, as indicatedby the labels “BT OFF” in time slots 150.

With conventional wireless communications circuitry of the type shown inFIG. 3, WLAN operations are blocked completely during the activeBluetooth time slots. As a result, with conventional circuitry 52 ofFIG. 3, WLAN data that is sent to circuitry 52 at a time such as time t₂or at a time such as time t₄ in FIG. 7 will be lost. Conventionalcircuitry 52 only allows WLAN data to be successfully transmitted orreceived at times such as time t₁ or time t₃, when Bluetooth integratedcircuit 60 of FIG. 3 is inactive. Particularly in environments in whicha premium is placed on low-latency and negligible packet loss, such aswhen supporting VoIP telephone calls, conventional arrangements of thetype shown in FIG. 3 can be disadvantageous.

Wireless communications circuitry 76 of the type shown in FIG. 4 can beused to support a simultaneous RX mode, which allows WLAN circuit 110and Bluetooth circuit 120 to receive incoming data at the same time.Because both WLAN circuit 110 and Bluetooth circuit 120 can be activeand receiving data at the same time, WLAN data can be received at timessuch as time t₂ in FIG. 7 as well as times such as times t₁ and t₃.Unlike conventional circuitry that blocks WLAN data during BT RX timeslots, wireless communications circuitry 76 can be used to receive WLANdata during BT RX time slots. As a result, the amount of WLAN data thatis blocked due to simultaneous Bluetooth activity is minimized. Inapplications such as VoIP telephone calls, where it is desirable tominimize data packet loss, the quality of the VoIP service that device10 can deliver may be improved significantly when using the simultaneousreceive functions of wireless communications circuitry 76.

A state diagram illustrating modes in which device 10 and wirelesscommunications circuitry 76 may operate is shown in FIG. 8. Theembodiment of wireless communications circuitry 76 that is described inconnection with the state diagram of FIG. 8 has a first transceiver thathandles wireless local area network (WLAN) communications, alsosometimes referred to as WiFi communications or IEEE 802.11communications and has a second transceiver is used to handle Bluetoothcommunications. This type of arrangement is merely illustrative. Ingeneral, wireless communications circuitry 76 and transceiver andcontrol circuitry 108 can be used to support any suitable communicationsprotocols. The description of WLAN and Bluetooth communicationsprotocols is an example.

As shown in FIG. 8, wireless communications circuitry 76 and device 10may operate in at least three states, state 152, state 154, and state156.

In state 152, Bluetooth circuit 120 is active in Bluetooth TX ordedicated RX mode, whereas WLAN circuit 110 is inactive. State 152corresponds to the third row in table 146 of FIG. 6. In state 152,switch SW1 is in position C and switch SW2 is in position E. WhenBluetooth circuit 120 is in transmit mode, a radio-frequency transmittercircuit in transceiver 116 is used to generate outgoing Bluetooth data(e.g., data that has been received via path 124). The transmittedBluetooth data is conveyed to antenna 78 via path 102, switch SW2, path90, switch SW1, path 81, filter 80, and antenna 78. An example of a timeduring which Bluetooth data is being transmitted by circuitry 76 is timet₄ in BT TX slot 148-1 of FIG. 7. When Bluetooth circuit 120 is indedicated RX mode, Bluetooth that is received from antenna 78 isconveyed to a receiver in transceiver 116 via antenna 78, filter 80,path 81, switch SW1, path 90, switch SW2, and path 102. Bluetooth datamay be received over the dedicated RX path 90 in this way at anysuitable time (see, e.g., time t₂ in BT RX time slot 148-2 of FIG. 7).

Circuits such as circuit 108 and processing circuitry 36 may have one ormore internal clocks. For example, Bluetooth circuit 120 and WLANcircuit 110 may have each have an internal clock or may access a sharedsystem clock. Using timing information from the clock circuitry andprotocols implemented in processing circuitry 36 and circuits 110 and120, circuits 110 and 120 and processing circuitry 36 can make decisionson when to switch between different modes of operation in wirelesscommunications circuitry 76. Consider, as an example, a situation inwhich WLAN circuit 110 is in a sleep state. At a particular time (orwhen a particular set of conditions are satisfied), the WLAN circuit 110wakes up to check for incoming data (as an example). As indicated byline 158, when the WLAN circuit wakes up to receive WLAN data, wirelesscommunications circuitry 76 transitions from state 152 to state 154.

During transition 158, WLAN circuit 110 issues control signals forswitch SW1 on path 106 that set switch SW1 to position B. WLAN circuit110 also issues control signals on path 104 that set switch SW2 toposition D. Making these adjustments causes signals from antenna 78 tobe diverted through coupler 86. Part of the incoming signal power isdirected to WLAN circuit 110 over shared RX path 96 and part of theincoming signal power is directed to Bluetooth circuit 120 over sharedRX path 94 and path 102. Because of the presence of coupler 86, theincoming signal power is reduced somewhat. However, both circuits 110and 120 are able to receive the incoming signal at the same time.Because both WLAN circuit 110 and Bluetooth circuit 120 are able tosimultaneously receive incoming radio-frequency signals, state 154 issometimes referred to as shared RX mode. State 154 corresponds to thesecond row of table 146 in FIG. 6. In the diagram of FIG. 7, time t₂ inBT RX slot 148-2 may be associated with state 154.

When wireless communications circuitry 76 and/or processor 36 determinesthat WLAN circuit 110 has completed its necessary WLAN receivingactivities (i.e., when no data needs to be received or when receiveoperations are finished), wireless communications circuitry 76 cantransition back to state 152, as indicated by arrow 160. Duringtransition 160, WLAN circuit 110 issues control signals for switch SW1on path 106 that set switch SW1 to position C and issues control signalson path 104 that set switch SW2 to position E. In state 152, WLANcircuit 110 is inactive and Bluetooth circuit 120 is either transmittingBluetooth signals or is receiving signals over dedicated RX path 90. Byswitching the receive path from shared RX path 94 back to dedicated RXpath 90, coupler 86 is bypassed and Bluetooth circuit 120 is assured ofreceiving high-quality incoming data.

During state 154, WLAN circuit 110 is active and Bluetooth circuit 120is active in shared RX mode. In state 154, when wireless communicationscircuitry 76 determines that WLAN circuit 110 needs to transmit data,wireless communications circuitry 76 transitions to state 156, asindicated by transition line 162. As an example, WLAN circuit 110 mayneed to transmit an acknowledgement packet. To make this transmission,the WLAN circuit 110 may wait until Bluetooth receive operations havebeen completed (e.g., when a BT RX slot 148-2 has just finished). Atthis point, Bluetooth circuit 120 becomes inactive.

As shown in FIG. 8, in state 156, WLAN circuit 110 is active and istransmitting data. Bluetooth circuit 120 is inactive. During transition162, control signals are issued on path 106 that set switch SW1 toposition A. When switch SW1 is in position A, transmitted WLAN data fromWLAN circuit 110 is passed to power amplifier 88 via TX path 98.Amplifier 88 amplifies the transmitted signal and provides the amplifiedversion of the transmitted signal to switch SW1 over path 100. Thesignal passes through switch SW1, is filtered by filter 80, and istransmitted wirelessly over antenna 78.

The position of switch SW2 is generally not critical in state 156,because no signals can be received or transmitted through switch SW2 solong as switch SW1 is in position A. Nevertheless, it may be desirableto set switch SW2 to position E as a default. In this position, switchSW2 defines a low-loss path for transmitting and receiving data fromBluetooth circuit 120. By placing switch SW2 in position E in state 156,switch SW2 will be ready to use in the event that wirelesscommunications circuitry 76 transitions back to state 152.

When in state 156, wireless communications circuitry 76 can transitionback to state 154 once WLAN transmission activity is complete, asindicated by line 164. Wireless communications circuitry 76 makestransition 164 when WLAN circuit 120 is needed to receive data. In state154, WLAN circuit 120 may be used to receive data while Bluetoothcircuit 120 again becomes active in shared RX mode. During transition164, control signals are issued on path 106 that place switch SW1 instate B and control signals are issued on path 104 that place switch SW2in position D.

When in state 156, wireless communications circuitry 76 can alsotransition to state 152, as indicated by transition line 166. Wirelesscommunications circuitry 76 makes transition 166 when Bluetoothoperations are required, but WLAN operations are not required. Forexample, a clock in WLAN circuit 110 may be used to determine that BTOFF slot 150 has expired. When a BT OFF slot expires, Bluetoothoperations may be required. If WLAN circuit 110 is not needed forreceiving data, wireless communications circuitry 76 can transition tostate 152, as indicated by line 166.

During transition 166, control signals are issued for switch SW1 on path106 that set switch SW1 to position C. Control signals are issued onpath 104 that set switch SW2 to position E. In state 152, WLAN circuit110 is inactive and Bluetooth circuit 120 is either transmittingBluetooth signals or is receiving signals over dedicated RX path 90. Byswitching the receive path from shared RX path 94 back to dedicated RXpath 90 during transition 166, coupler 86 is bypassed and Bluetoothcircuit 120 is assured of receiving high-quality incoming data.

While in state 152, it may become necessary to use WLAN circuit 110 totransmit data. For example, processing circuitry 36 may have data thatis to be transferred over a wireless local area network with whichdevice 10 is in communication. To transmit the data using WLAN circuit110, wireless communications circuitry 166 transitions to state 156, asindicated by line 168. During transition 168, control signals are issuedthat place switch SW1 in position A. This connects WLAN transmit path100 to antenna 78 and allows WLAN circuit 110 to transmit the desireddata. The state of switch SW2 in state 156 is immaterial to theoperation of WLAN circuit 110, but, if desired, may be left in positionE to facilitate a transition back to state 152 after the WLAN data hasbeen transmitted.

FIG. 9 shows an embodiment of wireless communications circuitry 76 inwhich coupler 86 has been implemented using a coupler that has an evensplitting ratio. With this type of arrangement, incoming signals on path92 are divided into two parts for respective paths 94 and 96. Becausethe power of the divided input signals on paths 94 and 96 is equal,couplers of this type are sometimes referred to as 2:1 splitters.Although shown as a 2:1 splitter in FIG. 9, coupler 86 may produce anysuitable ratio of output powers on its outputs, if desired.

In the embodiment of FIG. 9, wireless communications circuitry 76 has aninput amplifier interposed in path 92. Input amplifier 170 may, forexample, be a radio-frequency amplifier of the type that is sometimesreferred to as a low noise amplifier (LNA). The gain of input amplifier170 helps to offset the power loss that arises from the use of coupler86. With one suitable arrangement, the gain of input amplifier 170 maybe set to compensate almost exactly for the loss of coupler 86. Withthis type of arrangement, if the loss imposed by coupler 86 is −4 dB to−4.5 dB on each output path (as an example), the gain of input amplifier170 may be set to +8-9 dB, so that amplifier 170 overcomes the insertionloss of coupler 86. This is merely an illustrative configuration foramplifier 170 and coupler 86. In general, coupler 86 may exhibit anysuitable associated insertion loss and amplifier 170 may have anysuitable gain level to mitigate the loss imposed by coupler 86. Ifdesired, one or more input amplifiers such as amplifier 170 may be usedin wireless communications circuitry 76 and such amplifiers may beplaced in other suitable input paths (e.g., path 96).

Switches such as three-way switch SW1 and two-way switch SW2 may beimplemented using any suitable switching hardware. With one suitablearrangement, switch SW1 may be implemented using a single pole threethrow (SP3T) switch that is controlled by control signals provided on atwo-line control bus as shown in FIG. 10. If desired, three-way switchSW1 may be implemented using two two-way switches 172 and 174, as shownin FIG. 11.

FIG. 12 shows how switches may be incorporated into transceiver andcontrol circuitry 108. In the example of FIG. 12, Bluetooth circuit 120includes switching functionality in the form of two-way switch 84.Transceiver 116 and control circuitry 118 may be used to send andreceive data. Signals may be conveyed between switch 84 and transceiver116 over path 102.

Circuits such as WLAN circuit 110 and Bluetooth circuit 120 may beprovided using one or more integrated circuits. With one suitablearrangement, WLAN circuit 110 is provided using one or more integratedcircuits and Bluetooth circuit 120 is provided using one or moreintegrated circuits. With another suitable arrangement, which isillustrated in FIG. 13, the functions of WLAN circuit 110 and Bluetoothcircuit 120 are integrated into a common integrated circuit(WLAN/Bluetooth transceiver and control circuit 108). When twotransceivers are integrated in this fashion, a single control block maybe used for processing and control. In the example of FIG. 13,WLAN/Bluetooth integrated circuit 108 includes WLAN transceiver 112 andBluetooth transceiver 116, which are controlled by a common controlblock 114/118. This type of arrangement may be used with a separatetwo-way switch, such as switch SW2 of FIG. 4, or may be used withintegrated two-way switch such as switch 84 of FIG. 13. If desired, thefunctionality of other components such as switch 82, coupler 86, andamplifiers 88 and 170 may be integrated with circuitry of the type shownin FIG. 13 in the form of one or more integrated circuits.

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention.

1. Wireless communications circuitry comprising: transceiver circuitrycomprising a first transceiver circuit and a second transceiver circuit,wherein the first and second transceiver circuits communicate usingdifferent communications protocols and a common radio-frequencyfrequency band; an antenna that handles radio-frequency signals in thecommon radio-frequency frequency band; a radio-frequency couplercomprising an input and first and second outputs, wherein when thewireless communications circuitry is operated in a first mode, the inputreceives radio-frequency signals from the antenna and simultaneouslyprovides corresponding first and second reduced-power versions of thereceived radio-frequency signals to the first and second outputs,respectively, wherein the first reduced-power version of the receivedradio-frequency signals is received by the first transceiver circuit,and wherein the second reduced-power version of the receivedradio-frequency signals is received by the second transceiver circuit; afirst switch that is connected to the antenna and that has at leastfirst, second, and third positions, wherein the first switch is coupledto at least one of the first and second transceiver circuits when placedin each of the first, second, and third positions; and a second switchthat is coupled between the first switch and the second transceivercircuit, wherein when the wireless communications circuitry is operatedin a second mode, the first transceiver circuit is active and transmitsradio-frequency signals through the first switch and the antenna withoutpassing through the radio-frequency coupler.
 2. The wirelesscommunications circuitry defined in claim 1, wherein: when the wirelesscommunications circuitry is operated in the first mode, the first switchis placed in its second position to route radio-frequency signals fromthe antenna to the input of the radio-frequency coupler and the secondswitch is placed in its first position so that the radio-frequencycoupler is coupled to the second transceiver; when the wirelesscommunications circuitry is operated in the second mode, the firstswitch is placed in its first position to route radio-frequency signalsthat have been transmitted from the first transceiver to the antenna;and when the wireless communications circuitry is operated in a thirdmode, the first switch is placed in its third position and the secondswitch is placed in its second position so that the antenna is coupledto the second transceiver.
 3. The wireless communications circuitrydefined in claim 1, wherein: when the wireless communications circuitryis operated in the first mode, the first switch is placed in its secondposition to route radio-frequency signals from the antenna to the inputof the radio-frequency coupler and the second switch is placed in itsfirst position to route signals from the second output of theradio-frequency coupler to the second transceiver; when the wirelesscommunications circuitry is operated in the second mode, the firstswitch is placed in its first position to route radio-frequency signalsthat have been transmitted from the first transceiver to the antenna;and when the wireless communications circuitry is operated in a thirdmode, the first switch is placed in its third position and the secondswitch is placed in its second position so that the antenna is coupledto the second transceiver through the first and second switches.
 4. Thewireless communications circuitry defined in claim 1, wherein: when thewireless communications circuitry is operated in the first mode, thefirst switch is placed in its second position to route radio-frequencysignals from the antenna to the input of the radio-frequency coupler andthe second switch is placed in its first position to route signals fromthe second output of the radio-frequency coupler to the secondtransceiver; when the wireless communications circuitry is operated inthe second mode, the first switch is placed in its first position toroute radio-frequency signals that have been transmitted from the firsttransceiver to the antenna; and when the wireless communicationscircuitry is operated in a third mode, the first switch is placed in itsthird position and the second switch is placed in its second position sothat radio-frequency signals are conveyed between the second transceiverand the antenna through the first and second switches and withoutpassing through the radio-frequency coupler.
 5. The wirelesscommunications circuitry defined in claim 1, wherein: when the wirelesscommunications circuitry is operated in the first mode, the first switchis placed in its second position to route radio-frequency signals fromthe antenna to the input of the radio-frequency coupler and the secondswitch is placed in its first position to route signals from the secondoutput of the radio-frequency coupler to the second transceiver; whenthe wireless communications circuitry is operated in the second mode,the first switch is placed in its first position to routeradio-frequency signals that have been transmitted from the firsttransceiver to the antenna through the power amplifier; and when thewireless communications circuitry is operated in a third mode, the firstswitch is placed in its third position and the second switch is placedin its second position so that the antenna is coupled to the secondtransceiver through the first and second switches.
 6. The wirelesscommunications circuitry defined in claim 1, further comprising: storageand processing circuitry, wherein the storage and processing circuitryis coupled to the transceiver circuitry, and wherein the storage andprocessing circuitry is configured to generate data for wirelesstransmission and is configured to process wirelessly received data. 7.The wireless communications circuitry defined in claim 1, wherein thefirst transceiver circuit comprises a wireless local area networktransceiver circuit.
 8. The wireless communications circuitry defined inclaim 1, wherein the second transceiver circuit comprises a Bluetoothtransceiver circuit.
 9. The wireless communications circuitry defined inclaim 1, wherein the first transceiver circuit comprises a wirelesslocal area network transceiver circuit and wherein the secondtransceiver circuit comprises a Bluetooth transceiver circuit. 10.Wireless communications circuitry comprising: a first wirelesstransceiver circuit that transmits and receives according to a firstcommunications protocol in a given radio-frequency communicationsfrequency band; a second wireless transceiver circuit that transmits andreceives according to a second communications protocol in the givenradio-frequency communications frequency band, wherein the first andsecond communications protocols are different; an antenna; aradio-frequency coupler; switching circuitry that is responsive tocontrol signals and that routes radio-frequency signals to and from theantenna, wherein the switching circuitry includes a first switch thathas at least first and second positions and that is coupled between theradio-frequency coupler and the second wireless transceiver circuit,wherein the wireless communications circuitry is operative in at leastfirst, second, and third modes of operation, wherein: in the first modeof operation, the first wireless transceiver circuit is active andtransmits radio-frequency signals through the switching circuitry andthe antenna without passing through the radio-frequency coupler; in thesecond mode of operation, the first and second wireless transceivercircuit are both active and receive respective first and second versionsof identical radio-frequency signals through the radio-frequency couplerand the first switch is placed in its first position to routeradio-frequency signals from the radio-frequency coupler to the secondwireless transceiver circuit; and in the third mode of operation, thefirst wireless transceiver circuit is inactive and the second wirelesstransceiver is active and transmits and receives radio-frequency signalsthrough the switching circuitry and the antenna without passing throughthe radio-frequency coupler and the first switch is placed in its secondposition so that the antenna is coupled to the second wirelesstransceiver through the switching circuitry.
 11. The wirelesscommunications circuitry defined in claim 10 wherein the switchingcircuitry further comprises a second switch having at least a firstposition in which the second switch routes the radio-frequency signalstransmitted from the first transceiver to the antenna in the first modeof operation and a second position in which the second switch routes theradio-frequency signals from the antenna to the radio-frequency couplerin the second mode of operation.
 12. The wireless communicationscircuitry defined in claim 10 wherein: the switching circuitry furthercomprises a second switch having at least a first position in which thesecond switch routes the radio-frequency signals transmitted from thefirst transceiver to the antenna in the first mode of operation and asecond position in which the second switch routes the radio-frequencysignals from the antenna to the radio-frequency coupler in the secondmode of operation; the radio-frequency coupler has first and secondoutputs; and during the second mode of operation, the first wirelesstransceiver circuit receives the first version of the radio-frequencysignals from the first output of the radio-frequency coupler and thesecond wireless transceiver circuit receives the second version of theradio-frequency signals from the second output of the radio-frequencycoupler through the first switch.
 13. The wireless communicationscircuitry defined in claim 10 wherein: the switching circuitry furthercomprises a second switch having at least a first position in which thesecond switch routes the radio-frequency signals transmitted from thefirst transceiver to the antenna in the first mode of operation and asecond position in which the second switch routes the radio-frequencysignals from the antenna to the radio-frequency coupler in the secondmode of operation; the radio-frequency coupler has first and secondoutputs; during the second mode of operation, the first wirelesstransceiver circuit receives the first version of the radio-frequencysignals from the first output of the radio-frequency coupler and thesecond wireless transceiver circuit receives the second version of theradio-frequency signals from the second output of the radio-frequencycoupler; the first version and second version of the radio-frequencysignals have respective first and second signal powers; and the firstsignal power is greater than the second signal power.
 14. The wirelesscommunications circuitry defined in claim 10 wherein: the switchingcircuitry further comprises a second switch having at least a firstposition in which the second switch routes the radio-frequency signalstransmitted from the first transceiver to the antenna in the first modeof operation and a second position in which the second switch routes theradio-frequency signals from the antenna to the radio-frequency couplerin the second mode of operation; the radio-frequency coupler has firstand second outputs; during the second mode of operation, the firstwireless transceiver circuit receives the first version of theradio-frequency signals from the first output of the radio-frequencycoupler and the second wireless transceiver circuit receives the secondversion of the radio-frequency signals from the second output of theradio-frequency coupler; the first version and second version of theradio-frequency signals have respective first and second signal powers;and the first signal power is greater than the second signal power by atleast 3 dB.
 15. The wireless communications circuitry defined in claim10, wherein the given radio-frequency communications frequency bandcomprises a 2.4 GHz radio-frequency communications band.
 16. A methodfor using wireless communications circuitry in a handheld wirelessdevice comprising: storing data in storage on the portable wirelessdevice; with processing circuitry that is coupled to the storage,generating data for wireless transmission and processing wirelesslyreceived data; with an antenna and a first transceiver circuit in thewireless communications circuitry, communicating wirelessly in acommunications frequency band according to a first communicationsprotocol; with the antenna and a second transceiver circuit in thewireless communications circuitry, communicating wirelessly in thecommunications frequency band according to a second communicationsprotocol that is different than the first communications protocol; whenit is desired to simultaneously receive data with both the first and thesecond transceivers in a simultaneous receive mode, distributingradio-frequency signals from the antenna simultaneously to the first andsecond transceivers using a radio-frequency coupler and a switch,wherein the switch is coupled between the radio-frequency coupler andthe second transceiver circuit and wherein the switch is placed in afirst position during the simultaneous receive mode; and when it isdesired to transmit and receive data with the second transceiver circuitwhile not transmitting or receiving data with the first transceivercircuit, placing the wireless communications circuitry in a given modeof operation in which the first transceiver circuit is inactive and thesecond transceiver circuit is active and is transmitting and receivingdata and in which the switch is placed in its second position.
 17. Themethod defined in claim 16 further comprising: when it is desired totransmit wireless data through the antenna from the first transceiver,placing the wireless communications circuitry in a wireless local areanetwork transmit mode of operation in which the first transceiver isactive and transmits radio-frequency signals through the antenna. 18.The method defined in claim 16 further comprising: when it is desired totransmit wireless data through the antenna from the first transceiver,placing the wireless communications circuitry in a wireless local areanetwork transmit mode of operation in which the first transceiver isactive and transmits radio-frequency signals through the antenna,wherein placing the wireless communications circuitry in the given modein which the first transceiver circuit is inactive and the secondtransceiver circuit is active and is transmitting and receiving data andin which the switch is placed in the second position comprises placingthe wireless communications circuitry in a Bluetooth transmission modeof operation in which the second transceiver is active and transmittingBluetooth radio-frequency signals through the antenna.
 19. The methoddefined in claim 16, wherein the wireless communications circuitrycomprises an additional switch coupled between the radio-frequencycoupler and the antenna, wherein the additional switch has at leastfirst, second, and third positions, wherein the additional switch iscoupled to at least one of the first and second transceiver circuitswhen it is placed in each of the first, second, and third positions, andwherein placing the wireless communications circuitry in the given modeof operation comprises conveying radio-frequency signals between theantenna and the second transceiver circuit through the switch and theadditional switch and without passing through the radio-frequencycoupler.
 20. The method defined in claim 16, wherein the wirelesscommunications circuitry comprises an additional switch coupled betweenthe radio-frequency coupler and the antenna, wherein the additionalswitch has at least first, second, and third positions, wherein theadditional switch is coupled to at least one of the first and secondwireless transceiver circuits when it is placed in each of the first,second, and third positions, and wherein distributing theradio-frequency signals from the antenna simultaneously to the first andsecond transceiver circuits comprises distributing the radio-frequencysignals from the antenna simultaneously to the first and secondtransceiver circuits through the switch, the additional switch, and theradio-frequency coupler.